SOS Snail. BBC World Service

As a university student (a while ago, now…) I studied zoology and specialised in conservation biology, the study of biodiversity loss and figuring out ways to protect the living world. Back then I studied the tragic story of a troop of little snails, called Partula, that live on islands in the South Pacific – or at least they used to.

Partula snails were the victims of a botched attempt at biological control; giant snails were brought to the islands for people to eat, but instead the snail ended up demolishing local gardens and crops; another snail species – a predator – was then brought in to eat the big snails, but instead they began to munch the local species of Partula snails.

When I was studying this case of getting things horribly wrong, there was no happy ending. Of at least a hundred Partula species, a third went extinct and 11 or 12 other species were whisked away into captivity in the 1990s and kept from the brink of extinction in zoos around the world.

So, I was thrilled when I had a chance to make this documentary, which follows the story up to the present day. This cautionary snail tale may in fact contain a message of hope, as the zoo-bred snails are being taken back to their native home in the Pacific.